Under ideal exterior and studio and lighting conditions, shooting a precision test pattern in front of the camera before or after scene, is known to assist in achieving a high level of reproduction accuracy. However, there are an increasing number of applications and shooting conditions where including a test pattern in the scene is difficult. For example an officer pursuing a suspect in a police cruiser with a dashboard camera running, has more important issues than remembering to place a test chart in front of the camera. Secondly, a test pattern remaining in the field of view of a camera, for more than the length of time required to provide a useful reference, could obscure important information.
Thirdly, constantly exposed test elements in the pattern would be subject to damage and rendered useless by adverse weather conditions.